Basically as the post says, does anyone have any data on driveline losses/gains, 1/4 mile times/mph, and or dyno results from switching from a m6 or A4 to a th400? I'm just wondering what to expect as far as mph loss, E.T. gain/loss from going from a 6spd. to a th400 with my combo. So far the best time and mph are in my sig. The combo is still not tuned and should have been able to pull 120mph traps with my current combo with the 6spd. but I've only managed a 117.31 trap and a best E.T. of an 11.88 so far. I will be going with a th400 maual valve body with a 9" converter with around 4000 stall. Any opinions on what to expect?

Thanks
Matt

 

Matt,

You might want to consider a TH-350. It would be quite a bit faster than a TH-400 and you will have a hard time killing one. Either way you probably want a 2.75 first gear (stock is 2.52).

Daren

 

My rear wheel HP dropped from 670 (12.1% loss, chassis dyno vs engine dyno) with the M6, to 600HP (21.3% loss) with the TH400, high-stall, non-locking convertor. Running NA, there wasn't a lot of change in ET or MPH (not the figures shown in my signature)..... my inept M6 launches and shifting were a bigger defecit than the drive train losses. With the convertor allowing me to launch at 5,000rpm with the full shot of juice, I can't see where the RWHP really means much of anything..... its tons more torque from the starting line.....

 

I switched from a m6 to hughes performance th-350 with there 4000 soft hit converter about a year and I love it. My et really didn't change that much. My 60ft time went from sparadic 1.7's to consistent high 1.5's to low 1.6's and I believe that that is the reason my et stayed the same. The loose conveter is going to eat up hp and you will lose trap speed, but what you lose on the big end you'll you make up in quicker 60ft times.
As far as how much mph you'll lose you can probably count on at least 2-3 mph maybe more.

Randy

 

Wow thanks for the fast replies guys!!


Gump, I have done tons of research and talking to to a lot of tranny shops and they have all recommended a th400 for my combination. I failed to mention that my motor is a nitrous motor and that I plan to spray a 250 shot to it to get me in the low tens/ high 9's. The people that I have talked to stated that the th350 will take a lot more money and upgrades than a similar th400 to hold up to the same horsepower. The 2.75 first gear does seem like a good option, though.


Fred, thanks for the reply that is what I was looking for. What was the best E.T. and mph that you got with the 6spd. as compared to the auto? Was the driving the main reason that your times/E.T. stayed the same?

rje, how much mph did you lose from the swap?

Anyone regret the swap?

Thanks
Matt

 

On average I lost around 3 mph on motor. On the gas I ran 118 mph on a 75 shot with the m6, with the auto I ran 118 mph on a 125 shot. Don't worry about mph, I've never seen a race won by the guy with the most mph.

Randy